The present invention relates to a vehicle window shade and particularly to a control mechanism facilitating movement of the shade between a retracted position and an extended use position.
Shades for vehicle windows are becoming increasingly popular, particularly in southern climates where the sun load on a vehicle can be significant and cause passenger discomfort even with air conditioned vehicles, such as automobiles. Conventional shade mechanisms typically employ a spring-loaded manual roller shade which can be extended with a handle and locks over a hook for holding the shade in an extended use position covering a window. Some vehicles include elaborate control arm mechanisms which allow for the electrical operation of a shade. One such vehicle is a BMW 740iL Series, which provides such a window shade for only the rear window. Typically, passenger side rear windows do not have sufficient room to accommodate such complicated arms and electrical control mechanism necessary to hold the shade in an extended use position and adequately retract the shade.
The use of flat coiled springs as a window sash counterbalance is well-known as, for example, disclosed in U.S. Pat. No. 2,609,193. The application of this type of spring to the shade environment has not been necessary in view of the fact that most window shade mechanisms include a coil spring contained within the roller itself which provides tension for retracting the shade to a stored position. The rachet locking mechanism for such shades, however, can easily become jammed and become somewhat frustrating for the user when such an event occurs. When the shade is mounted within the door of a vehicle, this problem is compounded since access to the roller mechanism is limited. Thus, there exists a need an improved shade control mechanism for vehicle windows and one which is reliable, easy to use and preferably which can be motorized at a minimal expense and installed in a relatively small space.